The present invention relates to a radial piston machine and more particularly to a spherical piston pump having at least one spherical piston whose ball is adapted to roll on an outer cam ring or stator and cooperates with a piston element which slides in a radial bore of a rotor rotatable on a stationary control pintle which is provided with supply and discharge channels.
A spherical piston pump having the construction referred to hereinabove is known from German Patent DE-OS No. 2,908,096. The slidable cylindrical sleeve disposed in a snug fit relative to the rotor's radial bore and including an inner axial passageway ensures a sealing by means of surfaces between rotor and sleeve and overlaps the ball in a manner so as to provide between the ball and the sleeve a sealing by means of surfaces. The arrangement is so made to establish a rigid connection between the ball and the sleeve after assembly and to allow as a consequence an eventual replacement of the entire unit only.